Six years of nitrogen addition reduced ecosystem carbon sequestration capacity in a subtropical forestOA
Nitrogen(N)deposition profoundly influences carbon(C)cycling in terrestrial ecosystems.However,integrated studies on dynamics of net ecosystem C stock(NEC)under N deposition in subtropical forests remain limited,creating uncertainty in assessing their C sequestration potential.We conducted a 6-year field experiment using a randomized block design to investigate the effects of N addition at three levels(0,30,and 60 kg N·ha⁻¹·year⁻¹)on NEC and its components—aboveground C stock(AGC),belowground C stock(BGC),forest litter C stock(FLC),fine root C stock(FRC),and heterotrophic respiration C efflux(RhC).N addition significantly reduced AGC,BGC,FRC,and RhC,but increased FLC.As a result,NEC declined with N addition,with AGC contributing most to this reduction and FLC the least.The N-addition-induced reduction in soil water content appeared to be the primary driver of decreases in AGC and BGC and indirectly reduced FRC via suppressed fine root biomass.RhC dynamics were more strongly governed by fine root biomass than by microbial traits,thereby partially mitigating the NEC loss.While N addition rates had limited effects on NEC and most C stock components,RhC was significantly affected.These findings suggest that medium-to long-term N deposition may reduce the C sequestration capacity of subtropical forests.This study provides new insights for accurately assessing C sequestration potential under increasing N deposition.
Rudong Zhao;Yu Wu;Chang Liao;Yi Li;Qiuxiang Tian;Qinghu Jiang;Xiaoxiang Zhao;Jing Fang;Canlan Jiang;Feng Liu
State Key Laboratory of Lake and Watershed Science for Water Security,Wuhan Botanical Garden,Chinese Academy of Sciences,Wuhan 430074,ChinaHubei International Scientific and Technological Center of Ecological Conservation and Management in the Three Gorges Area,Engineering Research Center of Eco-Environment in Three Gorges Reservoir Region,Ministry of Education,China Three Gorges University,Yichang 443002,ChinaKey Laboratory of Soil Ecology and Health in Universities of Yunnan Province,School of Ecology and Environmental Science,Yunnan University,Kunming 650091,ChinaState Key Laboratory of Lake and Watershed Science for Water Security,Wuhan Botanical Garden,Chinese Academy of Sciences,Wuhan 430074,China Hubei Hongtai Group,Wuhan 430077,ChinaState Key Laboratory of Lake and Watershed Science for Water Security,Wuhan Botanical Garden,Chinese Academy of Sciences,Wuhan 430074,ChinaState Key Laboratory of Lake and Watershed Science for Water Security,Wuhan Botanical Garden,Chinese Academy of Sciences,Wuhan 430074,ChinaState Key Laboratory of Lake and Watershed Science for Water Security,Wuhan Botanical Garden,Chinese Academy of Sciences,Wuhan 430074,China Faculty of Life Science and Technology,Central South University of Forestry and Technology,Changsha 410004,ChinaState Key Laboratory of Lake and Watershed Science for Water Security,Wuhan Botanical Garden,Chinese Academy of Sciences,Wuhan 430074,ChinaCollege of Resources and Environmental Sciences,Nanjing Agricultural University,Nanjing 210095,ChinaState Key Laboratory of Lake and Watershed Science for Water Security,Wuhan Botanical Garden,Chinese Academy of Sciences,Wuhan 430074,China
农业科技
Global changeN depositionForest ecosystemC stockBadagongshan mountain
《Forest Ecosystems》 2026 (2)
P.412-419,8
supported by the National Natural Science Foundation of China(Nos.31700462,32171599).
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